ElectriCute
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Leaf Number: 550885

Keeping battery at 20% to 80%?

Wed Nov 24, 2021 4:48 am

As some of you know, I'm new to the Leaf, and EV in general. My main concern about my car is "battery degradation." This, of course, is something that happens to the battery over time. The idea is to keep that degradation as low as possible. I hear this 20 to 80% theory a lot. A range to keep your battery at in order to lengthen it's life. Why is this? Isn't charging it to 100% a good idea to take advantage of the car's max range? A Nissan customer service rep mentioned to me that charging it to 100% is fine, and as soon as you reach 100%, charging stops. So no trickle charging. Is, what he told me, correct in regards to newer Leafs, or all Leaf cars in general? Like all of us Leaf owners, we want to maintain the battery as best we can so that we get the longest life out of it. To be honest, all of this is rather confusing. What are your thoughts on this subject, please?

Thank you.

dmacarthur
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Leaf Number: 306556
Location: Vermont

Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 7:40 am

Others more knowledgeable will weigh in soon, but to begin with 80% charge is plenty of miles for most people's runabout uses and for us in particular it lasts us several days depending on use. It turns out to be stress-free to charge to 80% or so, and then not worry till it gets down to 30% or so. No real need to charge it full unless planning a trip in which case, go for it and don't worry. Main thing? Not to worry, you are gonna love the way it functions!
2015 Leaf sold
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Stanton
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Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 7:48 am

There's about a hundred threads on this topic...but since you are new to EV's (and the newer Leafs only charge to 100%), here's some simple advice:
  • set a charging timer to finish in the morning before you leave for work (which also lets the battery cool in the late evening)
  • plug in (that evening) when you go below 50% SoC
And some tips:
  • don't let any EV sit @100% SoC for long periods of time (e.g. more than a day)
  • don't let any EV sit <20% SoC (or VLB) for long periods of time
heat accelerates all forms of battery degradation, so try to avoid charging during the hottest parts of the day/year (for example, I avoid charging when my Gen1 Leaf shows >6 temperature bars).

Other than that, enjoy driving electric!
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goldbrick
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Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 10:30 am

The physics are well known and the batteries do lose capacity over time. Like with almost any chemical phenomenon, heat accelerates the process. Very high or very low SOC states are also accelerating factors. The worst case seems to be high SOC (eg 100%) and high heat. Thus the advice to not leave the car at fully charged for days at a time while it's hot outside.

Many of the studies that show all this can be found online but they are usually several years old. From what I've read here, it appears that the manufacturers are making better batteries every year and the ones you buy today perform much better than the ones available 5 years ago.

I like to think of it like exposure to UV rays. You can 'go crazy' and never leave the house without 100+ SPF on. That is probably sound advice and many dermatologists might recommend that. Or you can just be careful not to get sunburned and wear a hat and long sleeves or SPF 30 in the summer when you are going to be outside for a long time. If you can get 90% of the benefit for 10% of the trouble that seems like a reasonable path. I found that after accepting the fact that the battery degrades with time, I could worry about it less and enjoy it more.

alozzy
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Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 10:35 am

That's a good analogy goldbrick, hope you don't mind if I steal it!
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WetEV
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Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 11:06 am

Stanton wrote:
Wed Nov 24, 2021 7:48 am
There's about a hundred threads on this topic...but since you are new to EV's (and the newer Leafs only charge to 100%), here's some simple advice:
  • set a charging timer to finish in the morning before you leave for work (which also lets the battery cool in the late evening)
  • plug in (that evening) when you go below 50% SoC
Make the charging timer start so that about 40% of the battery is filled in one night. Or a bit more or less, depending on details.

Plug in below 50%. Will charge to between 80% and 90%. Adjust as desired.
WetEV
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LeftieBiker
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Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 12:09 pm

Nissan salescritters will say just about anything to sell a Leaf - as will most other salescritters and, of course, the Dreaded Salesvermin. They told customers that the original 75 mile range Leaf had 100 miles of range or more. So take what they say with a grain of salt.
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PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

dmacarthur
Posts: 354
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Location: Vermont

Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 3:23 pm

Make the charging timer start so that about 40% of the battery is filled in one night. Or a bit more or less, depending on details.

Plug in below 50%. Will charge to between 80% and 90%. Adjust as desired.

We use 5 hours of level 2 at our particular station. Timer on at midnight, off at 5 AM, all off-peak and adds about 35%. As stated above, plug in below about 40%.
2015 Leaf sold
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SageBrush
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Re: Keeping battery at 20% to 80%?

Wed Nov 24, 2021 3:28 pm

It is not too surprising that new to LEAF owners are confused by people who say charging to below 100% SoC is advisable, yet Nissan does not give the owner that option, implying that routine charging to 100% SoC is fine.

Answer: Nissan is wrong if the goal is to mitigate battery degradation. How wrong depends on the circumstances. The longer the car sits at 100% SoC, and in particular the longer the car sits at 100% SoC when the battery is hot, the worse the Nissan approach becomes.

OP: you will find that EVERY single owner in this forum who wants to slow down battery degradation takes steps of one form or another to do two things: reduce the time the pack sits at 100% SoC; and second, tries to charge after the pack has had a chance to cool down some in the hot months of the year. The actual implementation details vary from person to person because each person uses their car differently, and each person has their own inconvenience:benefit threshold.

Read the different approaches and adapt one to fit you. Follows is my personal advice to you:

Don't let perfect stop you from doing good enough
A battery stewing for an hour or two is a whole lot better than overnight
A battery stewing at 95% SoC or less is a whole lot better than stewing at 100%
A battery stewing at 80F is a whole lot better than stewing at 90F+

Make an effort, and get on with life. The car will thank you. You can probably gain 70 - 80% of the possible benefit by doing 15 - 25% of the optimal.
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. Cal
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03/18: 58 Ahr @28k miles. 10/21: 53.4 Ahr @ 40k miles
-----
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ElectriCute
Posts: 57
Joined: Fri Oct 29, 2021 5:35 am
Delivery Date: 24 Oct 2021
Leaf Number: 550885

Re: Keeping battery at 20% to 80%?

Thu Nov 25, 2021 4:58 am

dmacarthur wrote:
Wed Nov 24, 2021 3:23 pm
Make the charging timer start so that about 40% of the battery is filled in one night. Or a bit more or less, depending on details.

Plug in below 50%. Will charge to between 80% and 90%. Adjust as desired.

We use 5 hours of level 2 at our particular station. Timer on at midnight, off at 5 AM, all off-peak and adds about 35%. As stated above, plug in below about 40%.
I can charge during the time when it's off peak hours. I don't have the power source on a timer, but I can keep an eye on it through the phone app. During the high temps of the summer, I'll use the onboard timer on the car so it can charge during the night when the battery itself is cooler. I do have one other question about charging. Is it detrimental to the life of the battery if say I charge in small amounts, 30% to 60%, for example, when I don't have enough time to give a fuller charge, but a little bit extra for when I need more range? Just small charges when I get a chance to add a little juice, so to speak?

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